Method for the resolution of hydrocarbon vapors



50 so adj'sted-thattle product taken' tion will be conj ointly c by means Patented. Mar. 17, 193i ramen a. Henman, or arrastran,

ATE'l QFFICE AND NATHANIEL E', LOMIS, WESTEIELD, NEW

@15 DELWE METHOD FOR THE RESOLUTTQN. F HYDRDCBON VAIPQRS .applic-ation filed October 25, 192?. Serial No. 223,609.

This invention relatesto an improved method for the resolution of hydrocarbon vapors. Tn a preferred method petroleum oils to rform gasoline, a stream of petroleum oil is :flowed through a zone in which it is heated under pressure to a cracking temperature and thereafter held in a digesting Zone in which further cracking takes place. Cracked material is withdrawn in a continuous stream from the digesting zone and is ordinarily fractionated to separate therefrom a liquid containing principally the hydrocarbons of higher boiling point than the gasoline fraction, leaving a vapor phase containing substantially all the 'asoline hydrocarbons produced b cracking.

ur invention has for its objects the more efficient recovery of gasoline from said vapor phase and the production of a gasoline of enhanced stability.

The .drawing shows a diagrammatic vertical cross section of apparatus adapted to carry out the` referred embodiment of our method. The rawing andmethod of opera described. The'hydrocarbon vapors, from which hydrocarbons of higher boiling point than itA is desired to in# clude in gasoline have been removed, are supplied tothe apparatus from a number of cracking installations through pipes 1, 2, 3, and'l, dischar 'ng into pipes 5 and 6 an pass into rectiying towers 7` and 8, which are connected inparallel. These towers are preferably of the plate type and any number may be employed in parallel, depending on the capacity required. The plates 9 and 10 carry over ow pipes and vapor distributors, such as bellcaps, which, however, are not shown.l Partial condensers 11, 12, 13 and 14 are -located in the upper part of these towers of which the vapors may be par tially condensed by the circulation of a cooling medium such as water and/or cold feed stock passing tothe cracking apparatus.

Thesetowers are preferably operatedlunder a pressure in excess of atmospheric, 50 lbs. gage' having been found very suitable. The @1r-011e# drooling medium Supplied t0 -thecondensers .11,'12-,13 and le is preferably overhead for cracking l part and steam spray pipe yof tower 21.

d 29, from which it will have anend point ranging from 300 to 360 F. The term endpoint as herein applied to a vapor phase denotes that if a sample of said vapor phase were completely condensed and redistilled at normal pressure, it would show amaximum vapor spending to the end point mentioned. This product passes od through pipes 15 and 16,v

discharging into ipe 17. Liquid withdrawn from the base o columns 7 and 8 through pipes 18 and 19 discharging into pipe 20 is transferred to the intermediate section of a secondary rectifying tower 21, which is preferably operated at reduced pressure, lbs. gage having been found especially suitable. This column is equipped with plates 21a, which plates carry overflow pipes and vapor distributors, Partial condenser 22 is located in the upper 23 in the lower part The amount of steam and ,cooling medium supplied to this tower-through 23 and 22 respectively is preferably so adjusted that the overhead vapor has an end point of'300 to 360 F. "This is conducted away through pipe 26, and condensed in cooler 26a from which it flows through ipe 26". The naphtha withdrawn from the ase of column 21 through pipe 27 is cooled in the naphtha cooler 28 and passes oi1 through line is preferably withdrawn through line 30, treated in 30 to the extent necessaryto cause it to conform to market specifications and continuously return to the system by pipe 31,' discharging Yinto pipe 32. The treatmentA in 3()a refers to the well known treatment of oils with sulphuric acid and/or alkali or doctor Jsolution, and the like.

The vapors passing through pipe 17 are discharged into'J the intermediate or lower part of fractionating column.33. This is equipped with plates 33, which carry .overdistributors such as l ow pipes and vapor bellc`aps,.not shown. Column 33 preferably operates under substantially the same pressure as columns 7 and'8.` The vapors passing discharge into paroverhead through pipe'34 cooled 1n any tial condenser 35, whlch may be suitable manner.

densedifi' pass through pipe in the retemperature corre- The lidad-products con` such as bellcaps, not shown. y

uid withdrawn from ceiving drum 37. Uncondensed gases are di verted through pipe 38, while the liquid condensate is withdrawn through pipe 39 to pump 40 and elevated into the upper part of column 33 through pipe 41. The amount of i. Partial condenser. 441s located in Lthe upper part of theoolumnaiidsteam coil 45 in the base. This-column preferably operates under a loweri pressure than'column 33, 25 lbs'. gage having. been. found particularly suit- The amountof water and steam supplied through 44 and 45 respectively are preferably so adjusted that any normally gaseous constituents present are separated. and pass okthrough line' 46, either to an accumulator, or preferably vare compressed by meansof pump 47 and introduced into plpe 38. The liquid withdrawnfrom the base of column 43 through` pipe .48a is cooled in the naphthapooler 49 and passes into pipe 26h. The `hydrocarbon vapors passing through pipe38 are introduced into the lower part of absorptiontower 50. This tower is lequipped. with a, seriesof plates 50H, which carryy overflow pipes and vapor distributors. such as bell caps, (not-shown). Itis preferably operated under substantially the same pressure as columns 7, 8,"and 33.

.found particularly suitable.

Anuabsorption menstruurn is supplied to this column by means of pipe 51 and spray distributor 52.4 This menstruum ,preferably consists vof part of the oil whichvhas been ltreated and rey-introduced intow thel system through pipe 31. `The amount of absorption menstruum ispreferably so proportioned that only propane and hydrocarbons of lower boiling point escape through pipe 53,'discharging into pipe 46 and passing thereby to any suitable accumulator. Y

The liquid withdrawn from the base of 50 by means of pipe-54l is passed 4by means .of .pump 552 discharging through pipe 56, coil 57, andplpe 58 into the intermediate or lower part of al stabilizing column 59. This columnis equipped with plates 59 which carry overflow pipes and vapor distributors, (not shown), and is preferably operated under a, reduced pressure, 5`lbs. gage having been This ,column -may be supplied with absorption menstruum .through pipe 60, discharging into spray distributor 61 and may be heated at the base by steam introducedthrpugh pipe 62 to coil 63, the steam condensed passing off through pipe 64.- The absorption menstruum introduced bilizer .column59 is withdrawn through .pipe

66 and introduced'by means, of pump 67 to the chamber 68 to pass in heat interchanging -relation'ship to the l`oil flowing to column 59,

thereafterhpassing. orf through pipe 69,.to

v cooler 70,' and 'then by means of pipe 71 into pipe 26". ,All of the products passing into pipe'26b and'combining therein are of stable character and conform to market specifications and may be diverted to any suitable ac cumulator. Itwill be understood that the equipment shown is in illustration and not in llmitation and that various alternative procedures may be adoptedwithin the scope of the appendedclaims, in which it is' our intention to claim'broadly all novelty inherent in our invention. v

Weclaim: 1; The process of preparing marketable products from a mixture of hydrocarbons consisting chieiiy of compoundsfof the gasoline,range, which-comprises subjecting the mixture in vapor form to partial condensation to produce a first condensate requir' g chemical treatment and a second vapor wh ch requires. nochemical treatment and has an endpoint ofapproximately 3DO-350 ,separating the second vapor into liquid proff.' ucts'substantially `free of normally gaseous hydrocarbons and into a gas, lchemically treating the first condensate and blending the treated condensate withthe liquid products separated from the second vapor.

2,. The process according to claim 1 in which; the partial condensation is carried out under'higher than atmospheric pressure.

, FRANK A. HOWARD.

NATHANIEL E. LooMIs.

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